Die Bedeutung der Rehabilitation beim herzkranken Diabetiker nach chirurgischen Eingriffen

Patients with diabetes nowadays are not directly endangered by dysglycemia, but they suffer vascular complications. The diabetic patient with existing cardiovascular (CV) disease has a particularly high risk for further CV complications and, therefore, requires specific attention. These patients need an intense and multimodal therapeutic approach which includes a strong interdisciplinary cooperation between the cardiologist and the diabetologist. Cardiac rehabilitation can effectively improve prognosis of CV patients with numbers needed to treat (NNT) comparable to standard pharmacological treatment. In diabetics, after coronary surgery, metabolism frequently and markedly deteriorates, and this requires strict metabolic monitoring and close cooperation between the diabetes team and the other professionals (cardiologist, nurses, physiotherapists, psychologists . . .) to reduce complications arising from hyperglycemia and also hypoglycemia and to improve the CV risk factors by lifestyle changes. Frequently, diabetes is only diagnosed during the hospital stay for CV complication; therefore, in these patients, specific attention is required for teaching and inauguration of therapy. Due to the high risk of these patients and the need of qualified metabolic co-treatment, following CV surgery, diabetic patients should be treated preferentially in rehabilitation centres specialised in both cardiac and metabolic care. Recent studies indicate that a multimodal and aggressive approach in CV diabetic patients can markedly improve their prognosis.

[Practice guidelines: conservative treatment of fibroids]

The conservative treatment of uterine fibroids is essentially based on symptomatology and patient's choice of treatment. The gynaecologist must develop a clear therapeutic protocol based on clinical examination, available test results and consideration of patient preference. The therapeutic options include close surveillance, hormonal treatments, conservative operative endoscopy and arterial embolization.

Gluten sensitivity and neuromyelitis optica: two case reports

Neuromyelitis optica is a clinical syndrome characterised by acute transverse myelitis plus an acute or subacute optic neuritis with or without recovery. Although once believed to be a variant of multiple sclerosis, diagnostic criteria have recently been proposed for neuromyelitis optica, making it a clinically distinct syndrome. The term gluten sensitivity refers to a state of heightened immunological responsiveness to ingested gluten in genetically susceptible individuals, as indicated by circulating antibodies to gliadin. Several neurological complications have been described associated with gluten sensitivity ranging from peripheral neuropathy and cerebellar ataxia to an increased risk of epilepsy. Although myelopathy has been described in some case reports of coeliac disease, neuromyelitis optica has never been described in association with gluten sensitivity. We describe two cases of gluten sensitivity presenting as neuromyelitis optica with no previous history of significant gastrointestinal symptoms. Gluten sensitivity was confirmed by immunological and histological studies.

The Gly482Ser variant in the peroxisome proliferator-activated receptor gamma coactivator-1 is not associated with diabetes-related traits in non-diabetic German and Dutch populations

The peroxisome proliferator-activated receptor gamma coactivator-1 (PGC-1) is involved in regulation of fatty acid oxidation, skeletal muscle fiber type specificity, and gluconeogenesis. The prevalent Gly482Ser variant in PGC-1 was shown to be associated with type 2 diabetes in some but not all studies. Moreover, it is unclear whether it influences prediabetic subphenotypes in non-diabetic populations. We studied the association of this variant with glucose tolerance (oral glucose tolerance test), insulin sensitivity (euglycemic hyperinsulinemic clamp) of glucose disposal and antilipolysis, insulin secretion (hyperglycemic clamp, 10 mM), maximal oxygen consumption (VO(2)max, bicycle ergometry), and intramyocellular lipids (magnetic resonance spectroscopy, tibialis and soleus muscle) in a normal glucose tolerant German cohort (n = 423) and a normal (n = 65) and impaired glucose tolerant (n = 94) cohort from the Netherlands. No statistically significant association with an examined phenotype was detected in any of the study cohorts. Specifically, VO(2)max and the soleus-to-tibialis ratio of intramyocellular lipid contents as a surrogate parameter of fiber type specificity was not different between the genotype groups. We conclude, that the Gly482Ser variant in PGC-1 is not associated with diabetes-related traits or skeletal muscle fiber type composition in a non-diabetic German and Dutch population.

Effects of moxonidine vs. metoprolol on blood pressure and metabolic control in hypertensive subjects with type 2 diabetes

Subjects with type 2 diabetes experience an increased cardiovascular morbidity and mortality, related to a high prevalence of hypertension, dyslipidemia, and obesity. Antihypertensive treatment with beta-adrenergic receptor blockers may have deleterious metabolic consequences, including worsening of lipid profiles and insulin sensitivity. The centrally-acting sympatholytic agent moxonidine may improve these variables. In this randomised, double-blind multicenter study, the effects of two widely used antihypertensive agents--moxonidine (MOX) and the beta (1)-selective adrenergic receptor blocker metoprolol (MET)--on blood pressure and metabolic control were directly compared in hypertensive subjects with type 2 diabetes. Patients received either MOX (0.2 - 0.6 mg/d) or MET (50 - 150 mg/d) for 12 weeks, intending comparable blood pressure control. In total 200 patients were randomized. Here we report results from the per protocol population consisting of 127 patients (MOX 66, MET 61) but similar results were found in the ITT population. Reductions in systolic (SBP) and diastolic (DBP) blood pressures after 12 weeks were similar in both groups: In the MOX group, mean SBP (+/- SD) decreased from 154 +/- 12 to 142 +/- 17 mmHg and mean DBP from 91 +/- 9 to 83 +/- 9 mmHg. In the MET group, mean SBP decreased from 152 +/- 13 to 140 +/- 15 mmHg, and mean DBP from 90 +/- 8 to 84 +/- 10 mmHg. Mean HbA (1C) values did not differ between groups after 12 weeks (MOX 8.1 +/- 1.4 Hb%, MET 8.1 +/- 1.5 Hb%, intention-to-treat population). However, fasting plasma glucose decreased in the MOX group (median change - 5 mg/dl), but increased in the MET group (+ 16 mg/dl; p < 0.05). Median changes in the insulin resistance index (HOMA (IR)) were + 0.56 micro IU x mol/L (2) in the MET group, and - 0.27 micro IU x mol/L (2) in the MOX group. Correspondingly, fasting triglycerides increased with a median change of + 29.5 mg/dL in the MET group, but decreased in the MOX group (- 27.5 mg/dl; p < 0.05). These results indicate that MOX, unlike MET, may elicit beneficial adaptations in glucose and lipid metabolism in hypertensive subjects with type 2 diabetes, although mean HbA (1c) values did not differ. In long-term treatment in this high-risk population, MOX thus may decrease global vascular disease risk to a greater extent than MET.

Comparison of face-to-face and videoconferenced multidisciplinary clinical meetings

A trial of videoconferencing of multidisciplinary breast cancer clinical meetings between three public hospitals was conducted in an attempt to increase attendance by medical staff at the meetings, and thus facilitate multidisciplinary care for breast cancer patients. The videoconferences were compared with the previously existing face-to-face clinical meetings through questionnaires, attendance, number of cases discussed and anthropological analysis. Although more people attended the videoconferences than the face-to-face meetings, most of the participants in the trial preferred the face-to-face meetings to the videoconferences. The mean number of cases discussed at the videoconferences was significantly less than the mean number of cases presented at the face-to-face clinical meetings. The face-to-face meetings were informal, spontaneous and conducive to open discussion. In contrast, the videoconferences were formal and regimented. Multidisciplinary case discussion can be facilitated by videoconferencing. Some of the negative experiences we encountered could be overcome with changes in meeting format. Our experience may help others in setting up a successful multidisciplinary team via videoconference.

Trans-nasal endo-assisted pharyngoplasty: a cadaver study

A possible new technique of endoscopic pharyngoplasty is described and has been developed in cadavers. The trans-nasal route is used for endoscopic visualisation of the velopharyngeal sphincter. Hynes pharyngoplasty is performed using both trans-oral and trans-nasal routes. This approach allows better visualisation and performance of the Hynes pharyngoplasty at the desired level, "high" in the nasopharynx, without splitting the soft palate.

Serum adiponectin levels predict the effect of short-term dietary interventions on insulin sensitivity in humans

AIMS/HYPOTHESIS

Fat-rich diets can acutely induce insulin resistance. Data from adiponectin knock-out mice suggest that this effect might be increased in the absence of adiponectin. In the present study we tested whether plasma adiponectin concentrations influence changes in insulin sensitivity induced by a short-term dietary intervention in humans.

METHODS

We analysed data from 27 healthy, non-obese men with normal glucose tolerance. These men ate a diet high in fat and a diet high in carbohydrates for three days each.

RESULTS

The high-fat diet induced a significant drop in insulin sensitivity (determined by euglycaemic-hyperinsulinaemic clamp) compared to baseline (0.100+/-0.009 vs 0.083+/-0.007 micro mol.kg(-1).min(-1).(pmol.l(-1)), p=0.01). The drop in insulin sensitivity was more pronounced in subjects with low serum adiponectin (0.094+/-0.011 vs 0.077+/-0.010 micro mol.kg(-1).min(-1).(pmol.l(-1)), p=0.02) than in subjects with high serum adiponectin (0.103+/-0.011 vs 0.090+/-0.040 micro mol.kg(-1).min(-1).(pmol.l(-1)), p=0.16). In the whole group the high-carbohydrate, low-fat diet did not cause an increase in insulin sensitivity (0.095+/-0.007 vs 0.102+/-0.009 micro mol.kg(-1).min(-1).(pmol.l(-1)), p=0.06). However, insulin sensitivity was significantly increased in the subgroup with low serum adiponectin levels (0.084+/-0.013 vs 0.099+/-0.018 micro mol.kg(-1).min(-1).(pmol.l(-1)), p=0.01). In an additional multivariate analysis post-intervention insulin sensitivity was predicted by pre-intervention insulin sensitivity ( p<0.001) and adiponectin concentrations ( p=0.001).

CONCLUSIONS/INTERPRETATION

These data indicate that the reduction in insulin sensitivity achieved by a short-term high-fat diet is more pronounced in non-obese subjects with low serum adiponectin. Thus it is possible that the restriction of dietary fat and a diet high in carbohydrates might be particularly effective in subjects with low adiponectin such as obese or Type 2 diabetic individuals.

A Novel Nonsense Mutation in GCK Exon 9 Co-Segregates with Diabetes Phenotype

Maturity-onset diabetes of the young is an autosomal dominant form of non-insulin dependent diabetes mellitus and is caused by mutations in at least six different genes. In the most common forms, i.e. MODY2 and MODY3, the glucokinase (GCK) and the hepatocyte nuclear factor (HNF)-1alpha gene is affected, respectively. We have screened the GCK gene and HNF-1alpha gene by direct sequencing in three German families with early onset type-2-diabetes, possibly MODY. Next to known polymorphisms we have identified two novel intronic insertions in GCK and a novel non-sense mutation in exon 9 (C364 X). The latter mutation has an autosomal dominant inheritance pattern. Accordingly, this novel mutation segregates with diabetes phenotype in this family.

Verminderte Insulinwirkung bei subklinischer Leberzellverfettung

BACKGROUND AND OBJECTIVE

Steatosis of the liver is known to be associated with impaired insulin action and is considered to be a feature of the metabolic syndrome. In the present study we addressed the question whether liver fat content, as measured by proton MR spectroscopy ( (1)H MRS), in healthy subjects without clinical signs (hepatomegaly, elevation of transaminases) of relevant liver disease correlates with whole-body insulin sensitivity.

METHODS

21 (18 males and 3 females, age 35 +/- 11 years) non-diabetic subjects underwent the euglycemic-hyperinsulinemic clamp test for determination of whole body insulin action. Liver fat content was measured by means of proton MR spectroscopy ( (1)H MRS). Lipid content was calculated as percentage share of the lipid signal in relation to the entire signal of the spectrum (water and lipid signals). Clinically relevant steatosis of the liver was ruled out by standard magnetic resonance imaging (MRI). Subjects with a history of alcohol intake of more than 40 g/d were excluded from analysis.

RESULTS

In a single correlation analysis percentage liver fat strongly correlated with insulin sensitivity index (ISI) (r = 0.7, p = 0.001). After adjusting for the effects of percentage body fat (PFAT) percentage liver fat remained an independent determinant of ISI (p = 0.01).

CONCLUSION

Our results suggest that liver fat content is an important predictor of whole-body insulin sensitivity in healthy subjects. The correlation of liver fat content with insulin sensitivity was found in the absence of clinical steatosis and was independent of body fat content.

Minimal Metabolic Data Set for Patients at High Vascular Risk

Vascular events still represent the leading cause of death in the western world. The pathogenesis of atherothrombotic events is multifactorial. Epidemiological studies indicate that the presence of several concomitant risk factors, especially in the metabolic syndrome, markedly exacerbates the vascular risk. In the prevention and management of cardiovascular disease, a multi-dimensional risk factor approach is therefore required to reduce the "vascular burden". Consequently it is absolutely necessary to identify and to subsequently monitor these factors during intervention/therapy. The present MMDS represents a tool for the daily clinical routine to assess and document important cardiovascular risk factors. This data set is the result of a consensus of the two German working groups of the German Cardiology Society and the German Diabetes Society. The identification and detection of all relevant vascular risk factors should result in improved patient care and a more comprehensive documentation of cardiovascular risk factors in clinical studies.

Erythropoietin: a candidate compound for neuroprotection in schizophrenia

Erythropoietin (EPO) is a candidate compound for neuroprotection in human brain disease capable of combating a spectrum of pathophysiological processes operational during the progression of schizophrenic psychosis. The purpose of the present study was to prepare the ground for its application in a first neuroprotective add-on strategy in schizophrenia, aiming at improvement of cognitive brain function as well as prevention/slowing of degenerative processes. Using rodent studies, primary hippocampal neurons in culture, immunohistochemical analysis of human post-mortem brain tissue and nuclear imaging technology in man, we demonstrate that: (1) peripherally applied recombinant human (rh) EPO penetrates into the brain efficiently both in rat and humans, (2) rhEPO is enriched intracranially in healthy men and more distinctly in schizophrenic patients, (3) EPO receptors are densely expressed in hippocampus and cortex of schizophrenic subjects but distinctly less in controls, (4) rhEPO attenuates the haloperidol-induced neuronal death in vitro, and (4) peripherally administered rhEPO enhances cognitive functioning in mice in the context of an aversion task involving cortical and subcortical pathways presumably affected in schizophrenia. These observations, together with the known safety of rhEPO, render it an interesting compound for neuroprotective add-on strategies in schizophrenia and other human diseases characterized by a progressive decline in cognitive performance.

Diffusion tensor imaging for long-term follow-up of corticospinal tract degeneration in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a predominantly clinical and electromyographic diagnosis. Conventional MRI reveals atrophy of the motor system, particularly the pyramidal tract, in the advanced stages but does not provide a sensitive measure of disease progression. Three patients with different principal symptoms of ALS, i.e., with predominant involvement of the upper (UMN) or lower (UMN) motor neurons, or bulbar disease, respectively, underwent serial clinical examination including lung function tests, conventional MRI, and diffusion tensor imaging (DTI). MRI demonstrated changes in of the pyramidal tract without measurable variation on follow-up. The patient with UMN involvement showed remarkable progressive loss of diffusion anisotropy in the pyramidal tract. DTI might be useful, together with clinical follow-up, as an objective morphological marker in therapeutic trials.

[Deep pelvic endometriosis: management and proposal for a "surgical classification"]

Deep pelvic endometriosis presents essentially in the form of a painful syndrome dominated by deep dyspareunia and painful functional symptoms that recur according to the menstrual cycle, with the semiology directly correlated with the location of the lesions (bladder, rectum). It is essential to investigate these deep endometriosis lesions and draw up a precise map, which is the only way to be sure that exeresis will be complete. The treatment of first intention remains surgery, and medical treatment is only palliative in the majority of cases. Success of treatment depends on how radical surgical exeresis is. Based on analysis of the anatomical distribution of deep pelvic endometriosis lesions, a "surgical classification" is proposed with the aim of establishing standard modes for surgical treatment. Further studies are required to clarify the place and modes for pre- and postoperative medical treatment.

Relationship between serum adiponectin concentration and intramyocellular lipid stores in humans

The recently identified adipocytokine adiponectin has been shown to improve insulin action and decrease triglyceride content in skeletal muscle (by stimulating lipid oxidation) in mice. In the present study, we tested the hypothesis that high serum concentrations of adiponectin are associated with lower intramyocellular (IMCL) fat content by promoting lipid oxidation in humans. IMCL-content in predominantly non-oxidative tibialis anterior muscle and oxidative soleus was determined by proton magnetic resonance spectroscopy in a cross- sectional study involving 63 healthy volunteers. In a second set of experiments, changes in IMCL in both muscles were measured after a three days dietary lipid challenge (n = 18) and after intravenous lipid challenge (n = 12) with suppressed lipid oxidation under hyperinsulinemia. Adiponectin serum concentrations were found to be negatively correlated with IMCL in the oxidative soleus muscle (IMCL [sol]) (r = - 0.46, p < 0.001) independent of measures of obesity, but not with IMCL in the non-oxidative tibialis anterior muscle (IMCL [tib]) (p = 0.40). Adiponectin serum concentrations were negatively correlated with the observed increase in IMCL load after dietary lipid challenge in the tibialis (r = 0.53, p = 0.03) but not in the soleus muscle. During suppression of lipid oxidation by hyperinsulinemia, no effect of adiponectin on IMCL was observed in either soleus or tibialis muscle. Overall, the presented findings are consistent with the hypothesis that adiponectin promotes lipid oxidation in humans resulting in lower intracellular lipid content in human muscle. These results are consistent with animal data, where adiponectin could be shown to enhance lipid oxidation and reduce muscle triglycerides.

Mesenteric afferent nerves are sensitive to vascular perfusion in a novel preparation of rat ileum in vitro

Using novel in vitro preparations of vascularly perfused rat ileum, we investigated mesenteric afferent sensitivity to vascular perfusion. Gut (GPP) and vascular (VPP) perfusion pressures were recorded simultaneously with afferent discharge (AD). After preconstriction (L-phenylephrine), capsaicin (100 microM, gut lumen) caused a transient increase in AD and a sustained fall in VPP, supporting afferent modulation of vascular tone. In turn, AD was affected by vascular perfusion rate (VPR). Increasing VPR step-wise (0.6 to 1.0, 1.4 and 1.8 ml/min) caused concomitant falls in AD, returning at 0.6 ml/min. Terminating flow (5 min) increased AD. Afferent responses were independent of changes in GPP, vascular O2, or the gut "tube" ("gut-off"). In gut-off studies, where capsaicin (100 nM ia) still reduced VPP, flow-associated falls in AD were abolished by the enzyme neuraminidase (0.2 U/ml ia or extravascularly over 20 min). In contrast, increased AD after stopped flow was unaffected. We propose that mesenteric afferents "sense" changes in vascular perfusion. The precise stimuli (pressure and/or flow) and the physiological relevance to control of local circulation remain to be determined.

Arterial compression of the right common iliac vein; an unusual anatomical variant

Compression of the left common iliac vein by the right common iliac artery has been well described (Cockett's syndrome). The authors describe a case report of compression of the right common iliac vein by the right internal iliac artery. The patient presented with ipsilateral lower limb oedema. Venography showed smooth extrinsic compression of the right common iliac vein. The CT scan was initially interpreted as showing no extrinsic mass or obvious compressing lesion and lymphography was normal. It was the duplex scan which showed the bifurcation of the right common iliac artery crossing the right common iliac vein and causing significant extrinsic compression.

Dietary magnesium intake in type 2 diabetes

BACKGROUND

Magnesium deficiency is common in type 2 diabetes and may have a negative impact on glucose homeostasis and insulin resistance, as well as on the evolution of complications such as retinopathy, thrombosis and hypertension.

OBJECTIVE

To assess the dietary magnesium intake of patients with type 2 diabetes in Zurich, Switzerland and to compare the magnesium intake of diabetic and non-diabetic subjects.

DESIGN

The magnesium intake of 97 randomly selected patients with type 2 diabetes and 100 healthy, non-diabetic controls matched for age and sex was estimated using a diet history method. During winter and summer periods, mean daily magnesium intakes were calculated from detailed information given by the test subjects about their eating habits over the previous 2 months. The calculations were performed using EBIS, a computer program based on a German nutrient data base (BLS 2.3), with food items specific to Switzerland added or directly analysed when necessary.

RESULTS

The mean+/-s.d. daily magnesium intake of the male diabetic and male control subjects was 423.2+/-103.1 and 421.1+/-111.0 mg, respectively. The mean daily magnesium intake of the female diabetic and female control subjects was 419.1+/-109.7 and 383.5+/-109.7 mg, respectively. There were no significant differences in daily magnesium intake between the diabetic and the non-diabetic subjects and mean intakes in both groups exceeded Swiss recommended dietary intakes.

CONCLUSIONS

Dietary intake of magnesium appears sufficient in Swiss adults with type 2 diabetes and is unlikely to contribute to the aetiology of magnesium deficiency.

SPONSORSHIP

The Swiss Federal Institute of Technology, Zurich, Switzerland.

Selection of relevant dietary indicators for health

OBJECTIVE

To define a set of dietary components that are relevant determinants for health in Europe. The selected components are intended to serve as nutrition indicators for health in the European Health Monitoring Programme and, as such, must be limited in number, relevant to health in Europe and practical for all involved countries with respect to data gathering and comparability of data.

DESIGN

Major nutrition factors were determined by reviewing relevant epidemiological and clinical literature in nutrition and health as well as referring to reports from international expert groups, including the report from the project Nutrition and Diet for Healthy Lifestyles in Europe. The selection of factors was also based on the relative ease and cost involved for participating countries to obtain comparable and valid data.

RESULTS

The selected factors include foods or food groups as well as individual nutrients. Biomarkers are suggested for selected nutrients that pose the greatest difficulty in obtaining valid and comparable data from dietary studies.

CONCLUSIONS

The following list of diet indicators for health monitoring in Europe was agreed upon by the EFCOSUM group in 2001, in order of priority: vegetables, fruit, bread, fish, saturated fatty acids as percentage of energy (%E), total fat as %E, and ethanol in grams per day. Biomarkers were suggested for the following nutrients: folate, vitamin D, iron, iodine and sodium. Energy has to be assessed in order to calculate %E from total fat and saturated fatty acids.

[Laparoscopic treatment of genital prolapse: lateral utero-vaginal suspension with 2 meshes. Results of a series of 47 patients]

We report our experience with a new technique to treat genital prolapse: the laparoscopic lateral suspension with two meshes. This is a prospective longitudinal study of 47 women with genital prolapse. With a mean follow-up of 15.2 +/- 10 months (1-39), the anatomical result was perfect in 78.7% of the cases (37 patients). From the functional point of view, 89.3% were satisfied (42 patients). These good preliminary results need to be confirmed by other extensive studies.

Effects of intravenous and dietary lipid challenge on intramyocellular lipid content and the relation with insulin sensitivity in humans

An increased intramyocellular lipid (IMCL) content, as quantified by (1)H-magnetic resonance spectroscopy ((1)H-MRS), is associated with reduced insulin sensitivity. At present, it is unclear which factors determine IMCL formation and how rapidly IMCL accumulation can be induced. We therefore studied the impact of hyperinsulinemia and elevated circulating nonesterified fatty acid (NEFA) levels on IMCL formation and insulin sensitivity. We further evaluated the influence of a high-fat diet on IMCL storage. In the infusion protocol, 12 healthy male subjects underwent a 6-h hyperinsulinemic-euglycemic glucose clamp with concomitant infusion of Intralipid plus heparin. IMCL was quantified by (1)H-MRS in soleus (SOL) and tibialis anterior (TA) muscle at baseline and then every hour. IMCL levels started to increase significantly after 2 h, reaching a maximum of 120.8 +/- 3.4% (SOL) and 164.2 +/- 13.8% (TA) of baseline after 6 h (both P < 0.05). In parallel, the glucose infusion rate (GIR) decreased progressively, reaching a minimum of 60.4 +/- 5.4% of baseline after 6 h. Over time, the GIR was strongly correlated with IMCL in TA (r = -0.98, P < or = 0.003) and SOL muscle (r = -0.97, P < or = 0.005). In the diet protocol, 12 male subjects ingested both a high-fat and low-fat diet for 3 days each. Before and after completion of each diet, IMCL levels and insulin sensitivity were assessed. After the high-fat diet, IMCL levels increased significantly in TA muscle (to 148.0 +/- 16.9% of baseline; P = 0.005), but not in SOL muscle (to 114.4 +/- 8.2% of baseline; NS). Insulin sensitivity decreased to 83.3 +/- 5.6% of baseline (P = 0.033). There were no significant changes in insulin sensitivity or IMCL levels after the low-fat diet. The effects of the high-fat diet showed greater interindividual variation than those of the infusion protocol. The data from the lipid infusion protocol suggest a functional relationship between IMCL levels and insulin sensitivity. Similar effects could be induced by a high-fat diet, thereby underlining the physiological relevance of these observations.

Two novel prevalent polymorphisms in the hormone-sensitive lipase gene have no effect on insulin sensitivity of lipolysis and glucose disposal

Free fatty acids released during triglyceride lipolysis play an important role in obesity-associated insulin resistance of glucose disposal. Individual sensitivity of lipolysis to the suppressive effect of insulin varies greatly among healthy subjects. It is possible that genetic factors contribute to this variation. Among the many proteins involved in the regulation of lipolysis, hormone-sensitive lipase (HSL) represents a prime candidate for genetic variants contributing to the biological variation of insulin sensitivity of lipolysis. We determined the insulin sensitivity of lipolysis (suppression of isotopically [primed-continuous infusion of d5 glycerol] measured glycerol rate of appearance) and of glucose disposal, using a three-step (n = 20) or standard (n = 53) hyperinsulinemic euglycemic clamp in 73 healthy, unrelated subjects. To assess the possible role of genetic polymorphisms, we directly sequenced the coding region of the HSL gene and the noncoding exon B from these subjects. We identified two silent mutations and three amino acid polymorphisms: Arg262Met (prevalence, 5%), Glu620Asp (prevalence, 31%) and Ser681Ile (prevalence, 22%). The latter two are located in the regulatory domain of HSL but neither had a significant impact on insulin sensitivity of lipolysis or glucose disposal (with and without adjustment for obesity and age as covariates; all P values > 0.20). We conclude that a number of genetic polymorphisms in HSL exist, some of which are highly prevalent. Neither of the polymorphisms we identified in the coding region, however, contributed measurably to the biological variation of insulin sensitivity in our lean, healthy population.

Selective angiotensin II receptor antagonism reduces insulin resistance in obese Zucker rats

Effects of oral administration of the angiotensin II receptor antagonist (selective AT(1)-subtype) irbesartan on glucose tolerance and insulin action on skeletal-muscle glucose transport were assessed in the insulin-resistant obese Zucker rat. In the acute study, obese rats received either vehicle (water) or irbesartan 1 hour before the experiment. Although irbesartan had no effect on glucose transport (2-deoxyglucose uptake) in the epitrochlearis muscle, which consists mainly of type IIb fibers, acute angiotensin II receptor antagonism led to a dose-dependent increase in insulin action in the predominantly type I soleus muscle. Irbesartan at 25 and 50 mg/kg induced significant increases (41% and 50%, respectively; P<0.05) in insulin-mediated glucose transport. Moreover, these acute irbesartan-induced improvements in soleus-muscle glucose transport were associated with enhancements in whole-body insulin sensitivity (r=-0.732; P<0.05), as assessed during an oral glucose tolerance test. After chronic administration of irbesartan (21 days at 50 mg. kg(-1). d(-1)), glucose tolerance was enhanced further, and insulin-mediated glucose transport was significantly elevated in both epitrochlearis (32%) and soleus (73%) muscle. Chronic angiotensin II receptor antagonism was associated with significant increases in glucose transporter-4 (GLUT-4) protein expression in soleus (22%) and plantaris (20%) muscle and myocardium (15%). Chronic irbesartan-induced increases in whole-body insulin sensitivity were associated with increased insulin-mediated glucose transport in both epitrochlearis (r=-0.677; P<0.05) and soleus (r=-0.892; P<0.05) muscle. In summary, angiotensin II receptor (AT(1)-subtype) antagonism, either acutely or chronically, improves glucose tolerance, at least in part because of an enhancement in skeletal-muscle glucose transport, and the effect of chronic angiotensin II receptor antagonism on type I skeletal-muscle glucose uptake is associated with an increase in GLUT-4 protein expression.

Problems in analysis of data from muscles of rats flown in space

Comparison of hindlimb muscles of rats flown on Spacelab-3 or tail-traction-suspended showed that 11-17 h reloading post-flight might have altered the results. Soleus atrophied, plantaris, gastrocnemius and extensor digitorum longus grew slower, and tibialis anterior grew normally. In both flight and simulated soleus and plantaris, higher tyrosine and greater glutamine/glutamate ratio indicated negative protein balance and increased glutamine production, respectively, relative to controls. Aspartate was lower in these muscles. Reloading generally decreased tyrosine, but increased aspartate and glutamine/glutamate. These data showed that at 12 h of reloading after flight is characterized by reversal to varying extents of effects of unloading.

The role of the DNA mismatch repair system in the cytotoxicity of the topoisomerase inhibitors camptothecin and etoposide to human colorectal cancer cells

The DNA mismatch repair (MMR) system is involved in the correction of base/base mismatches and insertion/deletion loops arising during replication. In addition, some of the MMR components participate in recombination and double-strand break repair as well as cell cycle regulation and apoptosis. The inactivation of MMR genes, usually hMSH2 or hMLH1, is associated with human colorectal cancers and is responsible for the characteristic microsatellite instability (MSI)+ phenotype of these tumors. Because MMR is assumed to modulate cytotoxicity to various chemotherapeutic agents that act upon DNA, our objectives have been to define its possible involvement in the cytotoxicity of topoisomerase inhibitors. We have shown that colorectal cancer cell lines defective in DNA MMR exhibit an increased sensitivity to both camptothecin, a topoisomerase I inhibitor, and etoposide, a topoisomerase II inhibitor. Sensitivity to these drugs cannot be predicted by measuring endogenous levels of topoisomerase I and II. Our results also indicate that neither p53 status, nor cell cycle alterations correlate with the sensitivity of colorectal cancer cells to topoisomerase inhibitors. On the other hand, our data showing that resistance to these drugs can be achieved by the functional complementation of hMLH1 in an hMLH1-defective cell line have allowed us to establish that MMR is a critical determinant for chemosensitivity. Interestingly, our observations provide the rationale for the better responsiveness of MSI+ tumors to CPT-11, a camptothecin derivative, which we have observed in patients with metastatic colorectal cancers.

Context-dependent effects of steroid chemosignals on human physiology and mood

We examined the physiological and psychological effects of nanomolar amounts of steroids applied directly under the nose (Delta4,16-androstadien-3-one and 1,3,5,(10),16-estratetraen-3-ol). These potential human chemosignals were not consciously discernible in a strong-odor carrier (clove oil and propylene glycol). In a double-blind, within-subject, repeated-measures experiment with 65 subjects, we demonstrated that both steroids produced sustained changes in digit skin temperature and palmar skin conductance (an indicator of sympathetic nervous system tone) while the subjects were completing psychological questionnaires or reading. These effects, however, did not follow the sex-stereotyped pattern predicted by a sex attractant function. Both androstadienone and estratetraenol raised the skin temperature of men's hands and lowered it in women. Likewise, each steroid increased skin conductance, with a significantly greater effect on women than men. Women's responses were observed only in the sessions run by the male tester, an effect that may or may not be solely attributable to tester sex. Men's responses, in contrast, were not affected by this difference in socioexperimental condition. Similarly, women experienced an immediate increase in positive mood only in the presence of the male tester, while men's responses were unaffected by this socioexperimental context. One source of this sex difference may be the fact that the majority of women were in the late follicular phase of their menstrual cycle. Although it is premature to classify these steroids as pheromones, our data suggest that they function as chemosignals that modulate autonomic nervous system tone as well as psychological state.

Sustained human chemosignal unconsciously alters brain function

The human chemosignal, Delta 4,16-androstadien-3-one modulates psychological state without being consciously discernible as an odor. This study demonstrates that Delta 4,16-androstadien-3-one (androstadienone) alters cerebral glucose utilization both in subcortical regions and in areas of the neocortex not exclusively associated with olfaction. These widely distributed changes are consistent with modulation of an integrated neural network for regulation of emotional and attentional states. This is the first study to demonstrate the effects of a sustained chemosignal on brain metabolism and to show that they are similar to those of long acting chemical substances that affect psychological states. Moreover, this provides the first evidence that a human chemosignal has distributed effects on cortical processes and brain metabolism even when it is not detected consciously.

Impaired non-esterified fatty acid suppression is associated with endothelial dysfunction in insulin resistant subjects

In a recent study, we found a significant association between insulin resistance (IR) and disturbed flow-associated (endothelial-dependent) vasodilation in first-degree relatives of subjects with type 2 diabetes. However, the mechanisms linking insulin resistance and endothelial dysfunction (ED) have not been fully elucidated. Experimental data have pointed out that non-esterified fatty acids (NEFA) have a modulating effect on NO-synthase activity, and therefore on endothelial function. The aim of our study was to evaluate whether insulin resistance associated impaired NEFA suppression is present in subjects with ED. We examined 53 first-degree relatives (FDR) of patients with type 2 diabetes (32f, 21 m, mean age 35 years). Endothelial function was measured as flow-associated vasodilation (FAD%) of the brachial artery. Insulin sensitivity was evaluated with a standard hyperinsulinemic glucose clamp (insulin infusion rate of 1 mU/kg/min). While under fasting conditions, NEFA did not differ between groups with high or low FAD (0.415+/-0.033 vs. 0.394 +/- 0.040 mmol/l; p = n. s.), reduced FAD% was significantly associated with higher non-esterified fatty acids concentrations during steady state of the glucose clamp (0.072+/-0.022 vs. 0.039+/-0.016mmol/l; p=0.04). This association was independent of insulin levels under fasting conditions and during the glucose clamp. In conclusion, our results reveal a significant association between endothelial dysfunction and impaired non-esterified fatty acid suppression in insulin resistant subjects. As insulin resistance of lipolysis is a feature of the insulin resistance syndrome, these results suggest that elevated NEFA concentrations could play a role linking endothelial dysfunction and insulin resistance in vivo.